Ok so to update this and seek out some help, I went back to my mom's to look this over before I decide what needs replaced and what doesn't. As it turns out, the only loose part I found was the pivot point the swing arm for the spindle belt idler pulley attaches. This pulley rides on the back of the spindle belt and is under spring tension at all times.
One of the deck spindles is missing the grease zerk on the top of it and looking at the 'good' one it doesn't have a hex head and only spins when I try to unscrew it with a pair of pliers. Any advice on this? Despite one spindle missing a grease fitting they both spin freely.
The only other wear point I found was a tiny bit less than 1/32" of end play on the double pulley at the back of the deck. There's no wobble on any pullies and everything spins freely. No cracks in the deck.
Is it possible that this machine just killed the deck/spindle belt first and that, in-turn killed the PTO belt? I can't find anything else wrong here.
